Add CFB mode support. CFB uses segment size = block size.
Changes since V2:
 - Dropped CFB8, isn't widely used.
 - Simplified cfb_encrypt code.
 - Dropped code handling IV for last-partial-segment. One should set IV
   for new message anyway, so there little point in adding additional
   complexity there.
Changes since V1:
 - Add CFB8 support
 - Minor corrections in documentation.
Dmitry Eremin-Solenikov (1):
  Add CFB block mode support
 Makefile.in                |   4 +-
 cfb.c                      | 165 ++++++++++++++++++++++++++
 cfb.h                      |  87 ++++++++++++++
 nettle.texinfo             | 106 +++++++++++++++--
 testsuite/.gitignore       |   1 +
 testsuite/.test-rules.make |   3 +
 testsuite/Makefile.in      |   2 +-
 testsuite/cfb-test.c       | 287 +++++++++++++++++++++++++++++++++++++++++++++
 testsuite/testutils.c      | 179 ++++++++++++++++++++++++++++
 testsuite/testutils.h      |   7 ++
 10 files changed, 829 insertions(+), 12 deletions(-)
 create mode 100644 cfb.c
 create mode 100644 cfb.h
 create mode 100644 testsuite/cfb-test.c
-- 
2.14.2